Mobile e-commerce can be defined as commerce for mobile users made available via mobile devices such as mobile phones, PDAs (Personal Data Assistant), palmtop, etc. The mobile user has the possibility to do shopping, ticketing, banking, betting, trading via his mobile phones.
In web commerce goods, except electronic ones or services, are usually delivered later on. With mobile e-commerce, the user should be able to access the same commerce services with postponed delivery as the web but in addition, he must be able to access commerce services with short time delivery. For example, a user when on the move and thirsty, wants to get the soft drink from the automat right after having paid via his mobile phone. Another mobile user when visiting a city and wanting to see a movie expects to be able to collect the ticket at least before the beginning of the show.
In such situations, the entity performing the actual delivery, that could be a human being or a machine, needs to receive the authorisation for delivery quite rapidly. In addition, as in the case of the cinema ticket, the user needs to receive some sort of electronic receipt that he shows to the delivery entity to get the cinema ticket. Such an electronic receipt must fulfil the requirements:                It needs to be recognisable by the delivery entity        It can be used as a proof to show that the holder of the receipt has made the purchase and that the ordered goods and/or services can be delivered to the holder        It cannot be falsified        It cannot be duplicated or used twice        
Accordingly, there is a need for a receipt system in mobile e-commerce.
International patent publication number WO99/66436 discloses an electronic verified payment system (VPS) comprising a distributed verified trusted third-party system and method enabling electronic/digital transactions through real-time verification and authentication. The VPS includes hubs storing client data and connecting clients, such as users of mobile phones, palm-tops and digital television, to vendors to mediate secure electronic transactions. International patent publication number WO98/43211 discloses a digital payment transactions system wherein a broker generates and stores a secret number to be the start number for a chain of hash values by successive operations of a hash function. The values are associated with coins in a coin stick provided by the user, enabling secure payments in subsequent electronic transactions involving payments. Other systems and/or methods for electronic payments, of which some utilise a third party or a mediator, are disclosed in EP-A1-0865010, WO99/46720, U.S. Pat. No. 5,999,596, WO99/49404 and EP-A1-0971302. None of these, however, provide the user with a specific and reliable proof of the transaction made.
Other known systems for purchasing cinema tickets by telecommunication means, such as the one offered by Telenor Mobile in Norway, have only a very primitive scheme for receipt. After that the user confirms the acquisition of the tickets by entering through a telephone his PIN (Personal Identification Number) code, the user will receive a code, e.g. a 4 or 6 digit number. To collect his cinema tickets, the user presents the code at the ticket window. The ticket window attendant then compares the code presented by the user with one received from the system. If they match, then the attendant is authorised to hand out the purchased tickets to the user.
An example of an existing mobile e-commerce is depicted in FIG. 1. The user uses a mobile phone equipped with a browser, e.g. a WAP (Wireless Application Protocol) browser or a SIM (Subscriber Identification Module) Application toolkit browser, etc. allowing the user to browse on the World Wide Web via a gateway. The gateway can be a WAP gateway, an SMS (Short Message Service) gateway or any specific server capable of communicating with the browser on the mobile phone. The user visits a merchant's or vendor's web site. He contemplates the offers and selects the items that he wants. He pays for them through a payment scheme. The payment scheme may be for example based on a prepaid account, a credit or debit card or a bank account. He receives from the merchant a code that he can present when collecting the purchased items.
Such a system is simple but relies totally on the reliability of the merchant's system. It is only satisfactory if the delivery entity gets both the correct code and the correct information about the ordered tickets, e.g. theatre, movie, seats, etc. Otherwise, the user s will not receive the tickets that he has paid for. In case of failure, the user has only a code that is insufficient to prove that he has bought the tickets. Of course he will not be charged for the tickets in such a situation but this is not what he wants. It is quite frustrating not be able to watch the movie that one likes and has paid for.
As stated above, the current solution with a simple code is not sufficient since the user has to rely totally on the reliability of a vendor or merchant, and her/his system. Although the merchant may be honest and does not have the intention to play tricks on the user, if a fault occurs in his system the user will not get delivered the goods or services that actually has been bought, and usually paid for. Also, a mismatch between the ordered goods or services and what is actually delivered to the user can occur.